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[827/0] E. obscura... het vervolg from jonas on 2013-07-10 14:18:02.535388+02 -
This weekend I was in the haute fagnes and de Gaume with Elias de Bree. Quick summary.
- Eristalis alpina!
- three new km² for Eristalis obscura, in numbers! I think we can say we easily pick out the obscura's in the field! Much alike E. nemorum as said before.
- Chrysotoxum verralli
- Xylota ignava
- Blera
- Thyridanthrax fenestratus, Anthrax varius
- two new species for Belgium (TIpula trifascingulata and Agromyza archangelicae)
- and many many more!

Cheers
(ps: Rhingia rostrata reported in my previous message is in fact R. borealis. Not bad either)


[826/0] Eristalis obscura et al. from jonas on 2013-06-25 12:01:19.508746+02 -
Hi all,

besides our classic haute fagnes trips, we do have interest in the relatively unknown southern part of Belgium: 'de gaume'.
For butterflies it is a true hotspot, but also for other insects (eg grasshoppers) this is a nice area. I have never been here in spring, but its truly magnificent to watch flies!!!!

I visited the area by bike, for 3 days (14-15-16th of June). Most important findings:
- Microdon devius: at the known location, and a new location clearly linked to nest-bumps of Lasius niger!
- Paragus flammeus: abundant at one location
- Anasimyia lunulata: new locations
- Microdon myrmicae: new locations
- Chalcosyrphus valgus & Blera fallax: new locations
- Eristalis obscura (pseudorupium): found THREE males!!!! In 2010 Frank found this species in Belgium for the first time: in the haute fagnes, and he underligned the reduced wing markings. On the three males I found, the markings are reduced as well, and superficially, the species resembles E. nemorum!!! Accually: the species can be separated in the field rather quickly by the dark face (yellow in nemorum) and dark hairs on the back of F1. I caught 5 suspects, and 3 of them appeared to be E. obscura. In fact: there is another observation some 20 km away from mine, but I know for sure I cant 'publish' them here, so you will have to wait untill those pop up somewhere (...). Anyhow, it appears the species is strongly overlooked, and it might be quit dispersed in the region.
- Eristalis rupium
- Microdon cf mutabilis (did not find pupa... This is the giant from heathland, in contrary to the smaller ones from moist areas (myrmicae)).
- Brachyopa vittata
- Xanthogramma laetum
- Cheilosia ranunculi, pubera, nigripes, barbata,
- Rhingia rostrata
- Myolepta vara (my first: at last!!!)
- ...

To be continued :-)


[824/0] How to seperate panzeri from dorsata in the field? from Bastiaan on 2013-05-30 14:55:13.616207+02 -
Dear all,

last week, yes 1.5 days of sun! I went to check in all existing populations (Sphiximorpha subsessilis, Xantogramma leatum and B.dorsata) They where still there luckaly.
But during my walks I found also several Brachyopa panzeri on two still bleeding just cutted Fagus sylvatica (European Beech) trunks! So both species are in this area, no less than 1 km in distance from each other! That gave me the best opportunity to compare them better.

By using the key of Syrph the Net 2012 I found the best separation between them are the bristal colour of the hind margin of the scutellum. This character cannot be found in the Van Veen Key.

An other key character that cannot be found in both keys are the arista colouring: the arista in B.dorsata is almost black and in strong contrast with the 3rd antennal segment. The arista of B.panzeri is orange coloured all the way through.

Other character that I could not find in both keys are the darkened apical end of the vena spuria and wing tip in B.panzeri where B.dorsata does not have this.

The sensory pit characters are as in all keys correct but sometimes harder to see (depending on the correct viewing angle) especially in the field as of genital characters.

To sum up the new characters for field ID:

  • Scutellum hind margin with long black bristles (could be broken). Arista dark and in contrast with the 3rd antennal segment. No darker spots in the wing top or apical end of the vena spuria . -> B.dorsata

  • Scutellum hind margin without long black bristles (sometimes yellow bristles are present). Arista completely orange (no contract with 3rd antennal segment). Wing tip and apical end of the vena spuria darkened. ->B.panzeri
Hope this will add to a better separation between them in the field! Happy catching.

Cheers from rainy Brussels!

Bastiaan


[825/1] confirm from Bastiaan on 2013-06-11 10:35:14.821283+02 -
Can someone confirm these chars with his collection?

thanks,
   Bastiaan


[823/0] X.dives and stackelbergi and more from Bastiaan on 2013-05-30 13:08:56.180192+02 -
Hi all,
Due to the bad weather this May here in most parts of western Europe I decided to go to the south of France (near Nice) and heading up trough the alps back home.  Finally catching in a t-shirt :). The headlines where Xanthogramma dives and stackelbergi, Pipizella macullipennis. But still more to ID so far. It is always difficult without a proper key for a lot of genus-es I caught. Anyway, we had a great couple of days there. TODO: Merodon, Cheilosia, Epistrophe, Paragus etc... I will try to update under this thread.

Cheers,
Bastiaan


[820/0] Melangyna lucifera & others from jonas on 2013-04-25 14:04:18.390854+02 -
Dear all,
yesterday, Frank Van de Meutter, Elias de Bree and myself went to the hautes fagnes.
The haute fagnes are mostly visited from half may on, exceptionally in the beginning of may, and so, the early fliers are a total black spot in the Belgian database (see also Frank's message two years ago, he went to the fagnes 18th of april and came back with the first Belgian C. morio). Current records from beginning of may are mostly females, indicating the bulk has allready passed.

Anyhow, we gave it a shot - with a chance to come back with absolutely nothing! The weather was truly perfect, so enthousiasm was big :-) The first stop was near Recht. The first specimen caught here was Melangyna barbifrons! Then some Melangyna lasiophthalma. Then another barbifrons! Eventually we saw 46 M. barbifrons (all female!) together with some lasiophthalma and qaudrimaculata. We bottled some strange lasiophthalma in the meanwhile. High in the willows, we caught 3 Cheilosia morio, and few were seen but uncaught.

The mass of barbifrons was immens, at the streem nearby they were seen feeding on Anemone nemorosa (next to a O. geniculata).
At some point, Frank caught a Cheilosia orthotricha, feeding on willow - another true MEGA! Somewhat after noon, we moved a bit to higher ground (near Hoffai) and at a big willow quite far from any forest, another M. barbifrons was caught.

Although we hoped to find C. frontalis/nebuulosa, this will be for the next trip ;-)
At home; the funny looking lasiophthalma's appeared Melangyna lucifera!! Two females which are in the field, without considering M. lucifera, rather hard to find, although characters at home are unmistakably. Another species new to Belgium!

Yeah: haute fagnes in early season... blown away!
To be continued!!!!
Jonas


[822/1] Cheilosia frontalis from Frank on 2013-05-20 19:57:14.504447+02 -
Hi all,
after the remarkable catches at Recht in the belgian Hautes fagnes, we returned twice to the same spot. Good species seen were 2 Brachyopa dorsata, 10+ cheilosia morio, Platycheirus parmatus, P. splendidus, P. discimanus, Dasysyrphus pauxillus,... but the best catch probably was that of 1 male and 9 female Cheilosia frontalis!! Only the fifth observation of this species in Belgium.  This remarkable valley in Recht was originally doscovered by Jan Lucas who repeatedly visited this place in the '70 of last century. It were his observations that now made us to return to that overlooked place. Even more remarkable is that nearly all the rare species that he was able to discover back then now have been found again at the very same place - no loss of rare species has occurred here apparently over more then 40 years!! Many of these species have only a handfull of observations known in Beligum! (Melangyna barbifrons, Cheilosia frontalis, Platycheirus discimanus, Dasysyrphus pauxillus, ...)

We also managed to do an interesting ecological observation: one of the Cheilosia frontalis was seen settling on a leaf of Caltha palustris, and then slowly turning to the underside of the leave walking to the stem. I was too curious and then caught it, but I should have looked longer to see whether it was trying to lay its eggs. At least it gives a hint towards Caltha as a potential host plant of this species!

It is a cliché, but the very early spring species are still poorly known in these remote areas, and much is to be discovered!

regards

Frank


[821/1] Re: Melangyna lucifera & others from Bastiaan on 2013-05-03 14:55:29.639614+02 -
Whow guys! I am very jealous for sure! Thats 3 species I never caught ... ;-)